Train dispatching system for railroads



June 2, 136. R Q LEAKE ET 2,042,669

. TRAIN'DISPATCHING SYSTEM FOR RAILROADS Filed Aug. 14, 1929 2 Sheets-Sheet 1 NVENTOR 7 V .5 flaw 73% TTORNEY June 2, 1936.

R. .c. L EAKE ET AL TRAIN DISPATCHING SYSTEM FOR RAILROADS 2 Sheets-Sheet 2 Filed Aug. 14, 1929 mwgswy 'ATTORNIYEY Patented June 2 1936 UNITED STATES.

PATENT OFFICE TRAIN DISPATCHING SYSTEM FOR EAILROADS Application August 14, 192.9, Serial No. 385,740

42 Claims.

This invention relates to train dispatching systems, and more particularly to synchronous selector systems of the stepping relay type.

In accordance with the present invention it is proposed to control the switch machine and the way side signals of a large railway system through the medium of a comparatively few line wires, for the purpose of dispatching the movement of trains through the medium of wayside signalling indications.

The present invention contemplates the use of neutral relays connected in chain-like fashion so that the relays of one bank may be successivelypicked up and again dropped in synchronism with corresponding relays of another bank. One of the features of the present invention resides in a stepping circuit in which a particular relay is adapted to be energized only if the next preceding relay has already been deenergized, this feature affording certain additional protection, in that a foreign impulse on the line which may prevent a particular relay picking up as quick as it should will cause the stepping operation to cease entirely, allowing all of the relays to assume their deenergized position. In other words, in accordance with the present invention the system is so designated that the relays will assume their deenergized po- 'sition rather than follow some other stepping operation instead of the required stepping operation.

Qther objects, purposes and characteristic features of the system reside in the provision of suitable means for normally keeping theapparatus at rest, initiating it when required for use and again bringing it to rest after it has been operated through a predetermined number of cycles, as Well as other features which will become apparent as the description of the invention shown in the drawings progresses.

In describing the invention in detail reference will be made in the accompanying drawings, in which:

Fig. 1A represents the apparatus in the dispatchers oflice; and

Fig. 1B illustrates the apparatus located at a distant passing siding.

Referring to the drawings, it will be noted that if Figs. 1A and 1B are laid end to end the line wires are continuous, and these figures illustrate the train dispatching system of the present invention. Referring first to Fig. 1B the rails 10 of the main track of the railway system have been shown divided into sections by insulating joints ii, and also form part of a passing siding PS including -,,track rails 12 connected to the rails l through the medium of a track switch S at the west end or" the passing siding and a track switch S at the east end, which track switches are in practice controlled by suitable switch machines SM, and 8M respectively.

The east end of passing siding PS has associated therewith a main starting signal ME, a dwarf starting signal DE, a main entering signal MW and a take-siding signal 'DW. The switch machine SM is controlled by the switch machine relay SMR, and the signal ME, DE, MW, and DW are controlled by the relays SR and DB in a manner as more clearly described in the patent of S. N. Wight, Patent No. 1,889,457, dated November 29, 1932. In this connection it may be pointed out that relays MR, IE IE SR, DR and SMR are of the two position polar locking type, this locking being accomplished either by permanent magnets or by toggle springs. In the dispatchers office (see Fig. 1A) the entire railway system is duplicated in miniature, as conventionally shown by the miniature passing siding ps. Although the present invention, as conventionally shown, includes the apparatus of a large number of passing sidings, crossovers, draw bridges and alike, together with control means therefore, for convenience the apparatus associated with the passing siding PS only has been specifically illustrated.

At the east end of this miniature passing siding ps is an indicating lamp IE, which if illuminated indicates the occupancy of the detector track circuit associated with the east end of the passing siding PS including the track relay 2'1 and the track battery l4, whereas the indicating lamp IW shown at the left hand of the miniature track layout is illuminated if the detector track circuit at the west end of the passing siding PS, and including the track relay IT and the track battery I5, is occupied. Similarly, there is provided in proper juxtaposition with the east end of the miniature passing siding ps a switch machine lever SML for controlling the relay SMR,

PS and the line relay LR located at the east end of the passing siding PS, the remaining line relays having, for convenience, been omitted from the drawings. 7

Associated with each of these relays LR", LE, and LR. are the blank relays K K and K respectively, these relays only assuming their deenergized position while the line relays LR LR and LR assume their neutral biased position,

this being true because these relays K K and K are somewhat slow dropping and repeated reversals of the line relays will not permit these blank relays to assume their deenergized posi-'- tion; that is, they are deenergized only during the period of blank. 1

At the first way station the stepping relays A A A and A are successively pickedup in response to the repeated reversals of the line relay LR providing the blank relay K has at least momentarily assumed its deene gized position just prior to these repeated reversals. Similarly, repeated reversals of the line relay LE effects successive operation of the stepping relays B B 13 and B if once the relay B has been picked up due to closure of front contact I56 of relay A In the dispatchers ofiice the corresponding stepping relays havebeen designated with corresponding letters and numbers as the stepping relays of the way station, except that'the number precedes the letter instead of constituting an exponent to such letter. In other words, the stepping relay IAcorresponds to the stepping relay A and the stepping relay 4B corresponds to the stepping relay B These dispatchers ofiice stepping relays IA, 2A, 3A, 4A, IB, 2B, 3B, 4B and IC are operated successively in step-like fashion by the line relay LR and the circuit arrangement associated with these stepping relays is such as to in turn operate the master relLayMR, which master relay in turn repeatedly reverses the current flow in the stepping wire I8. In other words, the stepping relays operate the master relay MR, the master relay MR operates the line relay LR and the line relay LR in turn operates the next relay of the stepping relays.

The dispatchers office equipment also includes starting relays SR and SR indicating relays 1B and IR and the relays CR and W, the function of which will be more clearly described hereinafter.

At the first way station there are also provided'relays PR and QR for the purpose of initiating the normally at rest system after a change in track circuit occupancy takes place, the way station 2 being provided with similar relays PR and QR Having now pointed out the various elements of thesystern it is believed that their co-ordination and co-operation is best understood by considering the operation of the system.

Stepping-circuit operation.-Referring to the drawings it will be noted that each of the various relays, except the track relays IT and 2T and relay PR and PR assume their deenergized or retracted position, and that all of the signals at the east end of the passing siding P8 are at stop. Let us first consider the stepping features of the system without considering the function of the message circuit.

- Let us first assume that the dispatcher for some reason or other, operates the switch machine lever 'SML to the middle neutral position and then back to its normal full-line position. This is done in order to bring out the initiation of the system,

in that such movement of the lever SML causes the startingrelay SE to be picked up through the completion of the following circuit:beginning at the positive side of the battery 20, wires 2| and 22, upper winding of the relay SR wire 23, winding of the relay SR wires 24 and 25, switch blade 26 of the lever SML, wires 21 and 28 back to the negative terminal of the battery 20. The completion of this circuit not only picks up the relay SR but also picks up the relay SR With these relay armatures in their attracted position the relay SR is stuck up through the following stick circuit:beginning at the positive side'of the battery 20, wires 2| and 22, upper winding of the relay SR wire 23, winding of the relay SR wires 24 and 29, front contact 30 of the relay SR wire 3|, back contact 32 of the stepping relay IC", wire 33, to common return wire C connected to the negative terminal of battery 29 through wire 28. Similarly, the relay SR is stuck upthrough the following stick circuit: beginning at the positive terminal of battery 29, wires 2| and 35, winding of the relay SR wire 36, stick contact 31 of this same relay, wire 38, through two paths in multiple including respectively the back contact 39 of the relay K and 4|] of the relay CR to the wire 28 connected to the negative terminal of battery 20.

With the starting relay SR, in its attracted position the following circuit for the relay CR is closed:beginning at the terminal B of a suitable battery, front contact 42 of the relay SR wire 43, back contact 44 of the relay K wire 45, winding of the relay CR, wire 46 to the other terminal C of such battery. Energization of the relay CR completes the following pick-up circuit for the relay W:beginning at the terminal B of a suitable battery, front contact 41 of relay CR, wires 43 and 49, winding of the relay W, to common return wire C connected to the other terminal of said battery.

With the relay W in its attracted position the closure of contact 50 of this relay completes the following circuit for the lower winding of the master relay MR:beginning at the positive terminal of battery 20, wires 2| and 5|, front contact 58 of relay W, wire 52, back contacts 53, 54, 55,

56, 57, 58, and 59, respectively of the stepping,

relays IA, 2A, 3A, 4A, 'IB, 2B, and 3B, wire 60, lower winding of the master relay MR, wires 62 and 63 to the negative terminal of the battery 26. The closure of this circuit, does not,'however, operate the master relay MR, since the completion of this circuit tends to move its contacts 64 and 65 toward the left, and. since these contacts already have assumed the left-hand position they will not be changed. With the relay W now assuming its energized position the closure of the contact 61 applies current of negative polarity to the stepping wire I8, this because the contact 64 is in the left-hand position, thereby causing the line relays LR, LR and LR. to assume their left-hand position;

Movement of the contacts 68 and 69 of the line relay LE to the left-hand position, causes the stepping relay IA to be picked up through the following circuit:beginning at the positive terminal of battery 20, wires 2| and 10, back contact II of the relay K, wires 12 and I3, winding of the tact 82 of relay IA, wires 83 and 13, winding of relay I A, wires and 15, contact 68 of relay LR, wire 16, winding of the relay K wire 11, to the negative terminal of battery 26. It will be noted that the relay K is included in series with both of the circuit for the relay IA just traced, from which it is apparent that the relay K will presently assume its energized position and in so doing breaks the pick-up circuit of the relay IA including the contact 1| of the relay K", but the relay IA will remain energized because its stick circuit is still closed.

Picking up of the relay K breaks the energizing circuit for the relay CR at the contact 44 of relay K The relay CR thus assumes its retracted position, thereby again dropping its contact 85, and in so doing, bearing in mind that the relay IA is now energized, closing the following circuit through the upper winding of the master relay MRz-beginning at the positive terminal of battery 28, wires 2| and 5i, front contact 56 of relay W, wire 52, contact 53 cf the relay i A assuming its attracted position, wire 86, contact 85 of relay CR in its retracted position, wires 8! and 88, upper winding of the relay MR, wires 62 and 63, back to the negative terminal of battery 20. The flow of current in this circuit causes the contact 64 and 65 of the master relay MR to be moved to their right-hand position, thereby placing current of positive polarity on to the stepping wire I8, and thereby operating the line relays LR, LR and LR to their right-hand positions.

Also, it should be noted that even though picking up of the relay K, effects de-energization of the relay CR, and opening of the pick-up circuit for relay W at contact 47, this relay W will not assume its retracted position, because it is still energized through the following stick circuit:- beginning at the terminal B, back contact I8! of the stepping relay IC, wire I02, front contact I83 of the relay K9, wire I04, stick contact I05 of relay W, wires I86 and 49, winding of the relay W, to common return wire connected to the other terminal of said battery. It is thus seen that the relay W will remain energized until the last relay in the stepping relay series has assumed its energized position and has opened the stick circuit of relay W at the contact IOI. In other words, the stepping circuit remains closed at the contact 67 of relay W until the stepping operation has proceeded through the entire bank of stepping relays.

It should benoted that shifting of the contact 68 from its left-hand to its right-hand position breaks the energizing circuit for the relay IA, but before this relay IA can assume its retracted position the relay 2A has been picked up through the following circuit:beginning at the positive terminal of battery 28, wires 2I and 88, front contact 60 of the relay IA, wires 9| and 92, winding of the relay 2A, wires 98 and 95, contact 68 of the relay LR, wire 76, winding of the relay K wire I1, to the negative terminal of battery 28, thus causing the relay 2A to be picked up. With the relay 2A in its attracted position the following stick circuit for this relay is closed:beginning at the positive terminal of battery 20, wires 2|, 88, 91, and 98, stick contact 99 of the relay 2A, wires I86 and 92, winding of the relay 2A, wires 93 and 95, contact 68 of relay LR,- wires 16, winding of relay K winding 1! to the negative terminal of battery 20.

With the relay 2A assuming its attracted position, the contact 54 is lifted, but this lifting of contact 54 does not effect the application of ourrent to the master relay MR until the contact 53 of relay IA has assumed its retracted position, at which time the following circuit for the lower winding of the master relay MR is closedz-beginning at the positive terminal of battery 20, wires 2| and 5|, contact of relay W, wire 52, back contact 53 of relay IA, front contact 54 of relay 2A, wire 68, bottom winding of the master relay MR, wires 62 and 63 to the negative terminal of battery 28. Completion of this circuit effects operation of the master relay MR to the lefthand position, thereby applying polarity of negative'current to the stepping circuit, and operating the various line relays LR, LR and LR to the left-hand position.

With the line relay LR in its left-hand position, the stepping relay 2A is tie-energized, but before it can assume its de-energized position the stepping relay 3A is energized through the following circuit:beginning at the positive terminal of battery 20, wires 2 I, BI], and I 88, front contact I09 of relay 2A, wires I I8 and I II, winding of the relay 3A, wire H2 and I5, contact 68 of relay LR, wire I6, winding of relay K wire 17, to the negative terminal of battery 28. The

relays 4A, IB, 2B, and 3B are successively picked up through the pick-up circuit and stuck up through stick circuits which are analogous to the pick-up circuit for the relays 3A so that the circuits for relays 4A, IB, 2B, and 33 need not be specifically traced, it being deemed sufficient to trace the stick circuit for the relay 3B. This stick circuit may be traced as follows:beginning at the positive terminal of battery 28, wires H, 88, H4 and H5, stick contact II6 of the relay 33, wires II! and H8, winding of the relay 33, wires H9 and I5, contact 68 of the relay LR, wire 16, winding of the relay K wire IT, to the negative terminal of battery 20.

With this relay 3B energized and the relay 2B deenergized, current is shifted from the lower to the upper winding of the relay MR through a circuit readily traced in the drawings including contact 58 of relay 2B in its retracted position and contact 59 of relay 3B in its attracted position. The completion of this circuit causes the master relay MR to be moved to the right thereby applying positive current to the stepping circuit and effecting operation of the line relays LR, LR and LR to the right. This in turn causes the relay 43 to be picked up and the relay 313 to be dropped. Dropping of the relay 3B again shifts the current from the upper winding to the lower winding of the master relay MR,

thereby causing the line relays LR, LR and LR i to be operated to the left, which causes the stepping relay IC to be energized through its pickup circuit including front contact II3 of the relay 43. With the relay IC once energized its back contact IIlI is opened and the stick circuit for the relay W is broken, thereby effecting deenergization of the relay W. With the relay W deenergized the stepping circuit is opened at the contact 61 of this relay W, thereby preventing any further operation of the line relays LR, LR and LR and in fact causing their contacts to assume their middle-biased open position, which efifects de-energization of the stepping relay IC because its energizing circuit is broken at contact 68 of relay LR, However, while the relay 7 IC assumes its energized position, the stick circuit for the starting relay SR at the contact 32 of the relay I C is broken, so that the starting relay SRPassumes its deenergized position.

The starting relay SR however, remains in its energized position and as soon as the slowacting blank relay K assumes its retracted position in response to the pendant position of contact 68 of line relay LR", the energizingcircuit for the relay CR is again closed at the back contact 44 of relay K Obviously, with the relay CR again energized the relay W is caused to be energized, and its closure of the contact 61 causes negative current to again be applied to the stepping line wire i8. In this connection attention is directed to the fact that even though negative current is applied to the stepping wire twice in succession at this point in the operation, namely for the purpose of picking up the relay IC, as heretofore described, and now for the purpose of picking up the relay IA, this distinctive picking up of relays IC and EA is dependent upon the conditions of relays K and 4B. In this connection it should be remembered that the relay 4B was in its energized position when the relay IC was picked up and the relay K was in its energized position, whereas at the time now under consideration the relay 4B is deenergized and the relay K assumes'its deenergized position. Obviously the same cycle of operation of the stepping relays as heretofore described will now be repeated in that the cycle of operation has been re-initiated in response to the picking up of the relay CR.

Attention is directed at this time to the fact that the picking up of the relays CR and K in each case broke the stick circuit for the starting relay SR at the contact 40 of relay CR and the contact 39 of relay K This, starting relay SR in the first instant did not assume its deenergized position because it was held up by current flow in the upper winding of the relay SR The second picking up of the relays CR and K" however effect deenergization of the relay SR because the relay SR is no longer assuming its energized position and consequently there is no current flow in the upper winding of the relay SR and since the stick circuit of relay CR has now been opened at the contacts 40 and 39 (in multiple) of the relays CR and K, the relay SR will also assume its deenergized or retracted position, so that the third cycle of operation will not take place unless the relays SR and SR. are again picked up in response to the movement of a lever, or a change in the occupancy of a detector track circuit in a manner as more clearly pointed out hereinafter. This construction (contacts 39 and 40 in multiple) is resorted to to assure that the relay SR, does not drop until the entire starting function is complete, that is relay CR and K have both been picked up.

Referring now to the wayside equipment and bearing in mind that the first application of negative current to the stepping wire eiiected picking up of the relay IA in the dispatchers oflice, let us observe how the companion-stepping relay A is picked up in response to the first application of current of negative polarity to the line relay LR This application of current of negative polarity to the line relay LR causes energy to be applied to the slow-acting blank relay K but before this relay K has time to assume its energized position, the relay A is picked up through the following pick-up circuit:--beginning at the positive terminal of the battery I20, wires I2I' and I22, back contact I23 of the relay K wires I24 and IE5, winding of the relay A wires I26 and I21, contact I28 of the relay LE assuming its lefthand position, wire I29 and I30, to the negative terminal of the battery I20. The relay K assumes its energized position a moment later, and in response to the closure of the following circuit:beginning at the positive terminal of battery I20, wire I2I, contact I3I of relay LR assum- 5 in its left-hand position, wire I32, winding of the relay K wire I33, wire I30, to the negative terminal of battery I20. Attention is directed to the fact that the circuit just traced is closed when the line relay LR assumes either the right-hand or left-hand position, so that this relay K remains in its attracted position so long as the line relay LE is reversed at the usual normal stepping rate. As soon as the stepping relay A assumes its attracted position the following stick circuit for this relay is closed:-beginning at the positive terminal of battery I20, wires I2I and I35, stick contact I36 of relay A wires I31 and I25, winding of the relay A wires I26 and I21, contact I28 of line relay LR wires I29 and I30 to the negative terminal of battery I20.

It thus appears that the relay A is picked up synchronously with the relay IA through the means of circuits and devices substantially identical to that used for picking up of this companion relay IA. Similarly, with the relay A assuming its attracted position and with the line relay LR operated to the right, the relay A is picked up through the following pick-up circuitz-beginning at the positive terminal of battery I20, wires I2I and I38, front contact I39 of relay A wires I40 and MI, winding of the relay A wires I42, and I43, contact I28 of the line relay LE wires I29 and I30 to the negative terminal of battery I20. With the 'relay A once energized its stick circuit including its stick contact I44 is closed.

Similarly, the relay A is picked up through the front contact I45 of the relay A and is then stuck up through its stick contact I46 with the line relay LR in its left-hand position. Further, the stepping relay A is picked up through the front contact I41 of the relay A and is then stuck up through the stick contact I48 of the relay A with the line relay LE assuming its right-hand position.

Movement of the line relay LE to the left-hand position remembering that relay A is still energized, completes the following pick-up circuit for the stepping relay B :-beginning at the positive terminal of the battery I20, back contacts I39, I45 50 and I41 of the stepping relays A A, and A respectively, front contact I50, of the relay A line wire I5I, extending from the west end of passing siding PS to the east end of this passing siding PS, wire I 52, winding of the relay B wires I53 and I55, contact I56 of the line relays LR in its left-hand position, wires I51 and I58 to the common return wire C connected to the negative terminal of the battery I20. It is thus seen that the relay B is picked up in synchronism with the 60 relay IB.

With the relay B now energized movement of the contacts of line relay LR. to the right-hand position effects deenergization of the relay B but before this relay B can assume its retracted position the following pick-up circuit is closed for the stepping relay B :-beginning at the positive terminal of the battery 220, wires I60 and I6I, front contact I62 of the relay B wires I63 and I64, winding of the relay B wires I65 and I66, contact I 56 of the line relay LR' wires I51 and I58, to the negative terminal of battery 220. With the relay B once energized its stick circuit including the front stick contact I61 of this relay is picked up and its stick circuit is closed.

Similarly, movement of the contact I56 of line relay LR to the left with the relay B energized,

the relay 2B is picked up through a circuit including the front contact I68 of relay B and with the relay 13 once picked up it is stuck up through a circuit including its stick contact I69.

Similarly, with the relay B energized and the line relay LR then shifted to the right, the relay B is picked up through the front contact I'II] of the relay B Before this relay B however actually assumes its retracted position the relay B is stuck up through a stick circuit including its front contact I'II, after which shifting of contact I56 of the line relay LE to the left, opens the stick circuit for the relay B and causes this relay B to assume its retracted position. In the meantime, however, the first relay of another group of relays (not shown) may be picked up through the contact I12 of the relay B, if such another group of stepping relays is employed.

We have now pointed out how the system initiated and how it will run through two complete cycles of operation and will then be brought to stop, and how the stepping relays IA, 2A, 3A, 4A, IB, 2B, 3B, and 4B are picked up synchronously with the corresponding stepping relays A A A A B B B and B respectively. With this understanding of the system it is believed expedient to consider lever operation and train movement, and observe how a large number of message circuits may be sequentially closed to obtain distinctive controls over a comparatively few line wires.

M essage-circuz't operation.-Let us assume that the dispatcher wishes to move the track switch S to the take-siding position in order to accomplish this. movement of the switch S he will move his lever SML to the right hand position and in so doing will momentarily close the contacts 26', thereby effecting energization of the starting relays SR and SR and effecting initiation of the system, in a manner as described in detail in the foregoing description. This initiation of the system causes the stepping relays in the dispatchers office and the companion stepping relays at the way stations to be synchronously operated to their attracted position and back to their retracted position, until eventually the stepping relay 3B and the stepping relay B will momentarily assume their energized position simultaneously, and when this occurs this relay SMR is operated to its left-hand position through completion of the following message circuit:-be-- ginning at the negative terminal of a suitable battery, such as the battery M, contact I'I5 of the lever SML, wire I76, front contact I" of the stepping relay 3B, back contacts I18, I79, I30, IBI, I82, and [83 of the relays 23, IB, 4A, 3A, 2A, and IA, respectively, wire I84, contact 69 in its left-hand position, wire I85, contact 65 of the master relay MR in its right-hand position, wire I85, contact I8! of the relay K in its attracted position, message wire I9, wire I88 (see Fig. 13), front contact I89 of the: relay K wire I90, back contacts I9I and I92 of the relays B and B respectively, front contact I93 of the relay B wire I94, winding of the switch machine relay SMR, to common return wire C connected to the midpoint of battery M. The completion of this message circuit causes the switch machine relay SMR to be moved to the left-hand position, thereby operating the switch machine 8M to its takesiding position, providing of course that traffic conditions are such that the switch machine can be operated with safety, suitable approach locking means being used for this purpose. The syn-' chronous stepping relay system will operate through two complete cycles of operation at which time the starting relays SR and SR will again have assumed their de-energized position and therefore will not reinitiate the system.

Attention is directed to the fact that this message circuit, as well as all other message circuits, include contacts 65 and 69 of relays MR and LR, respectively, assurning opposite positions. This expedient is resorted to, because it is desirous to cut down the time during which the message circuit may be completed, this in order to avoid possibie overlap between two otherwise distinct message circuits. in other words, this expedient is employed to avoid a particular lever operating th wrong relay at the distant point, bearing in mind that it is possible for two adjacent stepping relays to be energized in slightly overlapped relation.

Let us now assume that there is a train standing on the side track of passing siding PS, and that this is an east bound train andmoves' over the switch S in response to clearing of the dwarf signal DE. The treading of this train upon the detector track circuit including the track relay 2T, will cause this track relay 2T to be de-energized, thereby causing the relay QR to be picked up through the following circuitzbeginning at the terminal B, contact 200, of the relay ET in its retracted position, wire 2m, contact 202, of the relay PR which relay is slow-dropping and has not yet assumed its de-energized position, wires 2% and 2M, winding of the relay QR to the other terminal C of said battery.

With this relay QR energized the starting relay SR is energized, during the at-rest period of the synchronous selector system, through the following circuitz-beginnin at the positive terminal of battery 20, wires 2I and 22, upper winding of the relay SR wire 23, winding of the relay SR wires 24 and 205, back contact IS'I of the relay K message wire I9, wire I88, back contact I89 of the relay K wire 201, front contact 208 of the relay QR wire 209, back to the battery 20 through the medium of the common return wire 0. It is thus seen that the synchronous selector system is initiated in response to dropping of the track relay 2T. Attention is directed to the fact that had the relay 2T assumed its retracted position during a cycle of operation of the synchronous selector system, the front contact 2!!! of the slow-acting relay K would have been closed, thus closing the following stick circuit for the relay QR :beginning at B, front contact 2II] of relay K wire 2E I, stick contact 2I2, wire 2I3 and 2M, winding of the relay QR to the other terminal C. From this it appears that the relay QR would remain stuck up during the cycle of operation then being consummated, and upon completion of such cycle the dropping of the contact I89 and i8! of relays K and K respectively, would complete the initiating circuit heretofore traced, thus initiating the system upon a new cycle of operation. A moment after this takes place the relay QR will drop because the contact 2 II] is opened while the initiating circuit is closed at contact I89 of relay K The relay QR. is slowdropping, as conventionally shown, so that the starting circuit just traced is closed sufficiently long to pick up relays SR and SR Attention is also directed to the fact that the contacts. I81, 2&2 and I89 of relays K, K and K synchronously shift use of the message wire from the starting function to the message transmitting function, and vice versa.

The track relay 2T now being in its retracted position causes negative current to flow from the battery 225 through the following message circuit completed momentarily while the stepping relays 4B and B simultaneously assume their attracted positionz-beginning at the negative terminal of battery 225, contact 226 of relay 2T in its retracted position, contact 221 of the relay B in its attracted position, contacts I93, I92, and I 9| of the relays B B and B respectively, in their retracted positions, wire I90, front contact I 89 of the slow-acting relay K wire I88, message wire I9, contact I81 of the relay K in its attracted position, wire I86, contact 65 of the master relay MR in its left-hand position, wire 228, contact 69 of the relay LR in its right-hand position, wire I84, contacts I83, I82, I8I, I88, I19, I18, and I11 of the relay IA, 2A, 3A, 4A, IE, 28, and 33, respectively, all in their retracted position, contact 229 of the stepping relay 4B in its attracted position, wire 230, indicating relay 1R wires 23I and 28, common return wire C, and wire 232 connected to the midpoint of battery 225.

Similarly, deenergization of the track relay IT causes the following message circuit to be completed while the stepping relay 4A and A simultaneously'assume their energized positionz-beginning at the negative terminal of battery 235, contact 236 of the track relay IT in its retracted position, contact 231 of the relay A' in its attracted position, contacts 238, 239 and 248 of the relay A A and A respectively, all assuming their retracted position, wire 24I, front contact 242 of the relay K wire 243, message wire I9, contact I81 of the relay K in its attracted position, wire I86, contact 65 of the master relay MR in its left-hand position, wire 228, contact 69 of the line relay LR in its: right-hand position, wire I84, back contacts I83, I82, and I8I of the stepping relay IA, 2A, and 3A, respectively, contact I 88 of the stepping relay 4A in its attracted position, wire 244, winding of the relay IR wire 245, common return wire C, and wire 246 connected to the midpoint of battery 235.

It has just been pointed out how the relay QR is stuck up upon dropping of the track relay 2T while the blank relay K is energized. Let us now observe how this relay QR is stuck up due to picking up of the track relay 2T while the blank relay K is energized. Under the conditions assumed the relays QR PR and 2T assume their deenergized positions and the relay K assumes its attracted position. If now the track relay 2T is picked'up, by reason of the fact that the train in question has moved off of this detector track circuit, the following pick-up circuit for the relay QR is momentarily closed:starting at B, front contact 288 of the track relay 2T, wires 268 and 26I, contact 292 of the relay PR in its retracted position, wires 283 and 284, winding of the relay QR to the return wire C. This relay QR will then be stuck up through the stick circuit here- .tofore traced. From this it appears that the system is also restarted in response to the picking up of the track relay 2T irrespective of whether such picking up of the track relay 2T occurs when the synchronous selector system is at rest or is operating at an intermediate point in a cycle of operation.

Let us now assume that the dispatcher wishes to clear the main starting signal ME at the east end of the passing siding PS. In order to do this he will move his signal lever SL to the righthand position, thereby closing the following twomessage circuits for the relays SR and DR when the relays IB--B and 2B'B respectively, assume momentary energized positions:-(l) beginning at the terminal B+ of a suitable battery such as battery 4 I, contact 248 of the signal lever SL, wire 249, contact I19 of relay IB in its attracted position, contacts I88, I 8|, I82 and I 83 of the relays 4A, 3A, 2A and IA, respectively, all

assuming their retracted position, wire I84, contact 69 of relay LR in its left-hand position, wire I85, contact 65 of relay MR in its righthand position, wire I86, front contact I 81 of relay K message wire I9, wire I88 (see Fig. 13), contact I89 of the relay K in its attracted position, wire I98, contact I9I of the relay B in its attracted position, wire 258, winding of the relay SR to common return wire C connected to the midpoint of battery M; and, (2) beginning at the terminal B+ of thesame battery 4|; contact 25I of the signal lever SL in its right-hand position, wire 252, contact I18 of the relay 2B in its attracted position, contacts I19, I88, I8I, I82, I83 of the relays IB, 4A, 3A, 2A and IA, respectively, all assuming their retracted position, wire I84, contact 69 of relay LR awuming its right-hand position, wire 228, contact 65 of relay MR in its left-hand position, wire I86, contact I81 of the relay Kin its attracted position, message wire I9, wire I88 (see Fig. 1B) contact I89 of relay K in its attracted position, wire I90, contact I9I in its retracted'position, contact I92 of relay B in its attracted position, wire 253, winding of the direction relay DR,'to common return wire C connected to the midpoint of battery M in the dispatchers ofiice. The completion of these two message circuits just traced, each of which lead from the positive terminal of the battery 4 I, cause the relays SR and DR to be operated to their right-hand positions, but since the direction relay DR is already in its right-hand position, this relay will not be operated. The relay SR, on the other hand, will be operated to the right to a position to clear the signal ME, this because the direction relay DR is to the right and the switch machine relay SMR is to the right. Clearing of signal ME signifies movement of east bound traflic over the main track.

Referring to Fig. 1B of the drawings it will be noted that the relay B is picked up through a line wire I5I extending from the west end of the passing siding PS to the east end of the pass-- ing siding. In some cases the distance from one way station to the next way station is so great that it may be desirable to omit this line wire I5I. In this case the relay such as relay 13 will be operated by a number of impulse counting or absorbing relays corresponding to the stepping relays of all the preceding way stations. In other words, in the case .under consideration if the line wire I5I were omitted the relay B would be preceded by four stepping relays located near and controlled by the line relay LR and the slow-acting relay K in exactly the same manner as are the relays A A A and A Similarly, there may be many other variations in the exact construction of the system disclosed,

for instance, any number of channels may be provided for a particular way station to obtain additional functions, such as indicating of the tion of this system after a change in occupancy aocaeea of a detector track; circuit, or a change in: any other traflic condition. Also, if desiredthe system may be one of the: continuously operating type by omitting the stopping and initiating mechanism. For instance, the position of the switch. machines may be indicated by suitable indicating lamps in the dispatchers office in exactly the same manner as detector circuit occupancy is indicated, in which event the system would be initiated: the switch machine is cranked by hand, so that the changed position of the: switch machine would be manifested in the dispatchers office. In other words, many of the sub-combinations of the entire system may be replaced by devices having similar functions without changing the ultimate result in the operation of the system and without departing from the present invention.

Having thus shown and described one rather specific embodiment of the present invention it is desired to be understood that the particular circuit. arrangement selected toillustrate an embodiment of the present invention has been selected for the purpose. of facilitating disclosure of the underlying principles of the present invention as well as its. operating characteristics, and not been selected with the intent of showing the exact construction preferably employed in practicing the invention or its scope, and that various changes, additions and. modifications may be made to: the specific construction shown, without departing from the spirit or scope of the invention or the idea of means underlying the same, except as demanded by the scope of the following claims.

What we claim as new is:-

1. In a train dispatching system of the synchronous selector type, the combination with a local dispatchers office and a distant way station; a steppingv wire and a common return wire connecting said oilice and way station; and means for applying potential of positive polarity, potential of negative polarity or no potential between said stepping wire and said common wire comprising; a two position polar relay of the locking type for connecting the positive or the negative terminal of a split battery to the stepping. wire, and a neutral relay having its front contact included in said stepping wire; whereby said neutral relay determineswhether or not potential shall. be applied to the stepping circuit and said polar relay determines the. polarity of said potential;

2. In atrain dispatching system of the synchronous selector type, the combination with a local dispatchers: oflice and a distant way station;. a stepping wire and a common return wire connecting said office and 'way station; and means for applying potential of positive polarits, potential. of negative polarity or no potential between said stepping wire and said common wire. comprising; a two position polar relay of the locking type for connecting the positive or the negative terminal of a split battery to the stepping wire, and a neutral relay having its front contact included in said stepping Wire; whereby said neutral relay determines whether or not potential shall be applied to the stepping circuit and said polar relay determines the polarity of said potential, a pick-up and a stick circuit for said neutral relay, means for momentarily closing said pick-up circuit to initiate said system, and means for momentarily breaking said stick circuit at one point at the end of a complete cycle of operation of said system.

3. In a train. dispatching system of the synchronous selector type, the combination with a local dispatchers ofiice and a distant way station; a stepping wire and a common return wire connecting said office and way station; and means for applying potential: of positive polarity, potential of negative polarity or no potential between said stepping wire and said common wire com prising; a two position polar relay of the locking type for connecting the positive or the negative terminal of a split battery tothe stepping wire, and a neutral relay having its front contact ineluded in said stepping wire; whereby said neutral' relay determines whether or not potential shall be applied to the stepping circuit and said polar relay determines the polarity of said potential, of a pick-up and a stick circuit for said neutral relay, means for momentarily closing said pick-up circuit to initiate said system, means for momentarily breaking said stick circuit at one point at the end of a complete cycle of operation of saidsystem, and means for alternately operating said polar relay to its right-hand and lefthand position so long as said neutral relay is energized.

4. Dispatchers ofilce equipment for train dispatching systems of the synchronous selector type comprising, an out-going stepping line including a line relay in series therewith, a master relay of the two-position locking type for applying positive potential to said stepping line when in one position and applying negative potential to said stepping line when in its. other position, a starting relay having a front contact included said stepping line, whereby said stepping line is deenergized' when said starting relay is deenergized, and means for energizing said starting relay to initiate said system and for deenergizing said starting relay at the end of each cycle.

5-. Dispatchers office equipment for train dispatching systems of the synchronous selector type comprising, an out-going stepping line including a line relay in series therewith, a master relay of the two-position locking type for applying positive potential to said stepping line when in one position and applying. negative potential to said stepping line when in its other position, a starting relay having a front contact included in, said stepping line, whereby said stepping line is deenergi-zed when said starting relay is deenergized, a: control: lever, starting means for picking up said starting relay when the position of said control lever is changed, and a stick circuit for said, starting relay broken momentarily at the end of each cycle of operation of the system.

6. Dispatchers office equipment for train dispatching. systems ot the synchronous selector type comprising. an outg.oing stepping line incuding a line relay in series therewith, a master relay of the two-position stick type for applyin positive potential to said stepping line when in one: position and applying negative potential to said stepping line when in its other position, a starting relay having a. front contact included in said stepping line, whereby said stepping line is deenergized said starting relay is deenergi zed, a control lever, starting means for picking up said starting relay when the position of said control lever is changed, a stick circuit for said starting relay broken momentarily at the end of each cycle of operation of the system, and means includng said starting means for again picking up said starting relay a moment after it has assumed its de energizedposition at the end of the first cycle of operation of the movement of said lever.

7. Way station apparatus for train dispatching systems of the synchronous selector type comprising, a line relay of the three-position type operated alternately to one and then to other of its energized positions during a cycle of operation of the system and assuming the deenergized position during the period of blank between successive cycles, a slow-acting relay, energizing circuits for said slow-acting relay closed when said line relay assumes either of its energized positions, whereby said slow-acting relay is deenergized only during said period of blank, a series of stepping relays, a pick-up circuit for the first stepping relay including a back contact of said slow-acting relay and the reverse contact of said line relay, and a pick-up circuit for the second stepping relay including a front contact of the next preceding stepping relay and the normal contact of said line relay.

8. Way station apparatus for train dispatching systems of the synchronous selector type comprising, a line relay of the three-position type operated alternately to one and then to the other of its energized positions during a cycle of operation of the system and assuming the deenergized position during the period of blank existing between successive cycles, a slow-acting relay, energizing circuits for said slow-acting relay closed When said line relay assumes either of its energized positions, whereby said slow-acting relay is deenergized only during said period of blank, a series of stepping relays, a pick-up circuit for the first stepping relay including a back contact of said slow-acting relay and a circuit for the second stepping relay including a front contact of the next preceding stepping relay and the normal contact of said line relay, and a stick circuit for each of said stepping relays including the same contact of said line relay as is included in the pick-up circuit of said stepping relay.

9. In a synchronous selector train dispatching system of the normally-at-rest type which includes a message wire and a common wire and which system is initiated from rest in response to connecting the message wire to said common wire, means for connecting said message wire to said common wire at the end of a cycle of operation of said system in response to a change in the position of a track relay even though such change takes place during the cycle period when the message wire must not be connected to said common wire comprising; a stick relay, a slow-acting relay, circuits for maintaining said slow-acting relay energized during the complete cycle of operation of the system and for deenergizing said slowacting relay during a period of blank, and a shorting branch circuit connecting said message wire and common wire including a back contact of said slow-acting relay and a front contact of said stick relay.

10. In a synchronous selector train dispatching system of the normally-at-rest type which includes a message wire and a common wire and which system is initiated from rest in response to connecting the message wire to said common wire, means for connecting said message wire to said common wire at the end of a cycle of operation of said system in response to a change in the position of a track relay contact even though such change takes place during the cycle period when the message wire must not be connected to said common wire comprising; a stick relay, a slowacting relay, circuits for maintaining said slowacting relay energized during the complete cycle of operation of the system and for deenergizing said slow-acting relay during a period of blank, a shorting branch circuit connecting said message wire and common wire including a back contact of said slow-acting relay and a front contact of said stick relay, a pick-up circuit for said stick relay and a stick circuit for said stick relay including a front contact of said slow-acting relay.

11. In a synchronous selector train'dispatching system of the normally-at-rest type which includes a message wire and a common wire and which system is initiated from rest in response to connecting the message Wire to said common wire, means for connecting said message wire to said common wire at the end of acycle of operation of said system in response to a change in the position of a track relay even though such change takes place during the cycle period when the message wire must not be connected to said common wire comprising; a stick relay, a slowacting relay, circuits for maintaining said slowacting relay energized during the complete cycle of operation of the system and for deenergizing said slow-acting relay during a period of blank, a shorting branch circuit connecting said message wire and common wire including a back contact of said slow-acting relay and a front contact of said stick relay, a second slow-acting relay, two pick-up circuits for said stick relay one including a front contact of such track relay and a back contact of said second slow-acting relay and the other of which includes a back contact of such track relay and a front contact of said second slow-acting relay, and an energizing circuit for said second slow-acting relay including a front contact of such track relay.

12. In a synchronous selector train dispatching system of the normally-at-resttype which includes a message wire and a common wire and which system is initiated from rest in response to connecting the message wire to said common wire, means for connecting said message wire to said common wire at the end of a cycle of'operation of said system in response to a change in the position of a track relay even though such relay change takes place during the cycle period when the message wire must not be connected to said common wire comprising; a stick relay, a slowacting relay, circuits for maintaining said slowacting relay energized during the complete cycle of operation of the system and for de-energizing said slow-acting relay during a period of blank, a shorting branch circuit connecting said message wire and common wire including a back contact of said slow-acting relay and a front contact of said stick relay, a second slow-acting relay, two pick-up circuits for said stick relay one including a front contact of such track relay and a back contact of said second slow-acting relay and the other of which includes a back contact of such track relay and a front contact of said second slow-acting relay, an energizing circuit for said second slow-acting relay including a front contact of such track relay, and a stick circuit for said stick relay including its own stick contact and a front contact of said first-mentioned slow-acting relay.

13. In a centralized trafiic controlling system of the normally at rest selector type, the combination with a selector system-normally at rest and provided with a stepping circuit having impulses impressed thereon when the system is in operation, of means for starting said system comprising, a stick relay having a front contact which if closed starts said system, anindicating contact for manifesting trailic conditions, a'slow acting.

7 said stepping circuit.

14. In a centralized traflic controlling system the combination with a. stepping line and a message line connecting a central oflice and a distant way station, normal-at-rest selector. apparatus at said ofiice and said way station, a slow acting relay at said o-ffice and way station energized upon intermittent energization of said stepping line, a front contact on each of said slow acting relays for rendering said selector apparatuses responsive to impulses on said stepping circuit, and a back contact on each of said slow acting relays for initiating the system through said message circuit toapply impulses to said stepping line.

15. In a centralized traific controlling system, the combination with a stepping line and a message line connecting a central oflice and a distant way station, normal-at-rest selector apparatus at said ofiice and said way station, a slow acting relay at said ofiice and way station energized upon intermittent energization of said stepping line, a front contact on each of said slow acting relays for rendering said selector apparatuses responsive to impulses on said stepping circuit, a back contact on each of said slow acting relays for initiating the system through said message circuit to apply impulses to said stepping line, and another front contact on said slow acting relays included in said message circuit for transmitting control impulses over said message circuit.

16. In a centralized traffic controlling system of the selector type for railroads, the combination with a central oflice and a plurality of way stations, a selector circuit connecting said oflicei and way stations, a line relay in said selector circuit at each way station, means in said central office for intermittently energizing said selector circuit to control apparatus at one of said way stations, a normally deenergized slow acting relay at each way station energized by each intermittent energization of said selector circuit through the medium of the line relay at such way station and sufficiently slow dropping to remain in its attracted condition until the next energization of said selector circuit, whereby the fact whether said slow acting relay assumes its energized or its deenergized condition manifests when intermittent energization of said selector circuit begins and ceases, a series of counting relays at each way station successively energized by the associated line relay, and an initiating circuit for the control of said counting relays including a back contact of said slow acting relay.

17. In a centralized traffic controlling system of the selector type for railroads, the combination with a central oflice and a plurality of way stations, a selector circuit connecting said ofiice and way stations, a line relay in said selector-- circuit at each way station, means in said central ofiice for intermittently energizing said selector circuit to control apparatus at one of said way stations, a slow acting relay at each way station energized by each intermittent energization of said selector circuit through the me- ,dium of theline relay at such ;way station and sufficiently slow dropping to remain in its'attracted condition until the next energization of said selector circuit, whereby the fact whether said slow acting relay assumes its energized or its deenergized condition manifests when intermittent energization of said selector circuit beginsand ceases, said system being normally at rest, and an initiating circuit for starting said system including a contact of such slow acting relay.

18. In a centralized traific'controlling system the selector type for railroads, the combination with a central office and a plurality of way stations, a selector circuit connecting said oflice. and way stations, a line relay in said selector circuit at each way station, means in said central ofdce for intermittently energizing said selector circuit to control apparatus at one of said way stations, a slow acting relay at each way station energized by each intermittent energization of said selector circuit through the medium of the line relay at such way station and sufficiently slow dropping to remain in its attracted condition until the next energization of said selector circuit, whereby the fact whether said slow acting relay assumes its energized or its deenergized condition manifests when intermittent energization of said selector circuit begins and ceases, a storing relay of the stick type which is picked up when the system should be re-initiated, and a stick circuit for said storing relay including a front contact of said slow acting relay.

19. In a centralized traflic controlling system of the selector type for railroads, the combination with a central oflice and a'plurality of way stations, a selector circuit connecting said oflice and way stations, at line relay in said selector circuit at said office and at each way station, means in said central ofiice for intermittently energizing said selector circuit to control apparatus at one of said way stations, and a slowacting relay at said office and at each way station energized during each intermittent energization of said selector circuit through the medium of the line relay at said ofiice and sufliciently slow dropping to remain in its attracted condition until the next energization of said selector circuit, whereby the energized and deenergized condition of said slow acting relays manifest respectively whether or not said selector circuit is intermittently energized.

20. In a centralized traffic controlling system of the selector type for railroads, the combination with a central office and a plurality of way stations, a selector circuit connecting said ofiice and way stations, a line relay in said selector circuit at said oflice and at each way station, means in said central office for intermittently energizing said selector circuit to control apparatus at one of said way stations, a slow acting relay at said oflice energized during each intermittent energization of said selector circuit through the medium of the line relay at said office and sufficiently slow dropping to remain in its attracted condition until the next energization of said selector circuit, whereby the energized and deenergized condition of said slow acting relay manifests respectively whether or not said selector circuit is intermittently energized, a series of counting relays at said ofiice, and an initiating circuit for the control of saidcounting 70 tion-with a central oifice anda'plurality of way-75 stations-a selector circuit connecting said oflice and way stations, a line relay in said selector circuit at said ofiice and at each way station, means in said central ofiice for intermittently energizing said selector circuit to control apparatus at one of said way stations, aslow acting relay at said ofiice energized during each intermittent energization of said selector circuit through the medium of the line relay at said .office and sufficiently slow dropping to remain in its attracted condition until the next energization of said selector circuit, whereby the energized and deenergized condition of said slow acting relay manifests respectively whether or not said selector circuit is intermittently energized, said system being normally at rest, and an initiating circuit for said system including a contact of said slow relay.

22. In a traflic controlling system for railroads, the combination with electrically operated means operable to impress a plurality of electrical current impulses on the stepping circuit of the seleotor system, a cycle demarking relay which assumes its energized position on the first of such impulses and remains energized until the end of the last impulse, a series of stepping relays the first of which can only be picked up if the cycle demarking relay is at that time deenergized and the others of which can only be picked up if the next preceding relay is up, and the proper kind of impulse is impressed on the stepping circuit, and means for transmitting a control impulse when a particular one of said stepping relays is assuming its energized position.

23. A centralized traflic controlling system comprising in combination, a line circuit, means for selectively applying positive or negative energy to said line circuit, a polar line relay having contacts capable of assuming either of two positions in accordance with the polarity of. the energy applied to said line circuit, a neutral relay, an energizing circuit closed for said neutral relay when the contacts of said polar relay assume either of their positions, stepping relay means, and a circuit for initiating said relay means controlled in accordance with the position assumed by the contacts of said polar relay during the pick-up period of said neutral relay.

'24. A centralized trafiic controlling system comprising in combination; a line circuit; a polar line relay included in said line circuit, said relay having contacts operable to either of two polar positions in accordance with the polarity of the energization of said line circuit; a slow acting neutral relay; an energizing circuit closed for said neutral relay whenever the contacts of said polar relay assume either of their polar positions; a series of stepping relays; and an energizing circuit for the first stepping relay of said series including a particular polar contact of said line relay and a back contact of said neutral relay.

25. A centralized traflic controlling system comprising in combination, a line circuit having a polar line relay included therein, a normally deenergized neutral relay having an energizing circuit closed when said polar line relay assumes either of its polar positions, selector apparatus, and a circuit for initiating said selector apparatus closed only if said polar line relay assumes a particular polar position only while said neutral relay still assumes its deenergized position.

26. In a centralized traflic controlling system of the selector type for controlling trafiic on railroads, the combination with a line circuit con- ?necting a central ofiice and a plurality of way stations and including .a line relay at said'centrai ofiice and at each of said way stations, of a series of stepping relays in said central ofiice and at each of said way stations, a primary relay in said central ofiice for applying current impulsesto said line circuit, energizing circuits controlled by the line relay in said office for causing the stepping relays at said office to be energized sequentially one relay for each impulse onsaid line circuit, and energizing circuits including. front contacts of said stepping relays for intermittently actuating said primary relay.

27. In a centralized trafiic controlling system of the selector type for controlling trafiic on railroads, the combination with .a line circuit connecting a central ofiice and a plurality of way stations and including a line relay at said central oflice and at each of said way stations, of a series of stepping relays in said central oflice and at each of said way stations, a primary relay in said central oflice for applying current impulses to said line circuit, energizing circuits controlled by the line relay in said ofiice for causing the stepping relays at said oflice to be energized sequentially one relay for each impulse on said line circuit, means for intermittently actuating said primary relay, each actuation being caused by the last of said stepping relays to be energized, and means governed automatically in accordance with a change of traflic conditions at any one of said way stations for causing a first actuation of said primary relay.

28. In a centralized traffic controlling system of the selector type for controlling traflic on railroads, the combination with a line circuit con' necting a central oflice and a plurality of way stations and including a line relay at said central ofiice and at each of said way stations, of a series of stepping relays in said central ofiice and at each of said way stations, a primary relay in said central oflice for applying current impulses to said line circuit, energizing circuits controlled by the line relay in said ofiice for causing the stepping relays at said ofiice to be energized sequentially one relay for each impulse on said line circuit, means for intermittently actuating said primary relay, each actuation being caused by the last of said stepping relays to be energized, a control lever at said central office for transmitting distinctive control impulses over said selector type system, and means governed in response to the movement of said control lever for causing a first actuation of said primary relay.

29. In a centralized traffic control system for railroads, a control ofiice, a plurality of way stations, a stepping circuit, automatic impulsing cuit, step-by-step means at each of said stations and said control office all operated in synchro nism by the application of said impulses to said stepping circuit, and a starting circuit extending between 'said control ofiice and said way stations capable of being closed at each station only a predetermined time after said stepping circuit has been deenergized.

30. In a centralized trafiic control system for control of switches and signals at a field station along the railroad track from a central ofiice by impulses on line wires, a stepping line circuit ex tending from the control oflice to the field station, a polarized line relay in said line circuit at the field station, a series of neutral stepping relays at the field station, circuits energizedfrom a local source of current at the field station and con trolled by said line relay for energizing said stepping relays sequentially one at a time, and means at the station controlled in accordance with the polarity of the first energization of said line circuit for determining whether or not said series of stepping relays shall be operated at all by subsequent operations of said line relay.

31. In' a centralized trafilc controlling system of the selector type for controlling trafiic on railroads; a normally deenergized stepping line circuit connecting a control ofiice and afield sta-' tion; a line relay at the control ofiice and another at the field station in series in said line circuit; a series of stepping relays at the control office and another series at the field station, each series being controlled by its respective line relay to cause said stepping relays to pick up successively, one for each impulse repeated by such line relay; an impulsing relay for applying an impulse of one polarity or the other to said stepping line circuit for each time it is actuated, when such impulsing relay has been rendered efiective to apply the first impulse tosaid line circuit; a cycle controlling relay for rendering said impulsing relay effective to apply a first impulse to said line i circuit; and circuit means for actuating said impulsing relay upon the picking up of each successive stepping relay of. said series in the control ofiice.

32. In a centralized traffic controlling system of the selector type for controlling traflic on railroads; a stepping line circuit connecting a control office and a field station; a line relay at the control oifice and another at the field station in series in said line circuit; a series of stepping relays at control oflice and another series at the field station, each series being controlled by its respective line relay to cause said stepping relays to pick up successively, one for each impulse repeated by such line relay; an impulsing relay for applying an impulse to said stepping line circuit for each time it is actuated when such impulsing relay has been rendered eliective to apply the first impulse to said line circuit; a cycle controlling relay for rendering said impulsing relay effective to apply a first impulse to said line circuit; circuit means for actuating said impulsing relay upon the picking up of each successive steppingrelay of said series in the control ofiice; and means controlled both from the control oifice and the field station for picking up said cycle controlling relay.

33. In a centralized trafiic controlling system of the selector type for controlling traffic on railroads; a stepping line circuit connecting acontr-ol oflice and a field station; a line relay at the control ofiice and another at the field station in series in said line circuit; a series of stepping relays at the control oflice and another series at the field station, each series being controlled by its respective line relay to cause said stepping re= lays to pick up successively, one for each impulse repeated by such line relay; an impulsing relay for applying an impulse to said stepping line circuit for each time it is actuated when such impulsing relay has been rendered efiective to apply the first impulse to said line circuit; a cycle controlling relay for rendering said impulsing relay effective when said cycle controlling relay is picked up; a slow acting cycle demarking relay controlled by said line relay at the control office so as to be picked up at the beginning of each series of impulses and to be dropped at the end of such series; a pick up circuit for said cycle controlling relay capable of being closed only when said cycle demarking relay is dropped away; a stick circuit for said cycle controlling relay closed-until the last of-:said stepping relays is picked up, when said stick circuit is once closed; and circuit means for actuating said impulsing relay upon the picking up of each stepping relay successively except the first stepping relay, which first actuation is delayed until the picking up of said-cycle demarking relay.

34. In a centralized traflic controlling system of the selector type for controlling traffic on railroads; a polarized stepping line circuit connect ing acontrol ofiice and a field station; a polar line relay at the control office and'another atthe field station included in series in said polarized stepping line circuit; a series of stepping relays at the control office and another atthe-fieldjstation, each series being controlled by its respective polar line relay to cause said stepping relays to pick up successively, one for each impulse repeated by such polar line relay; an impulsing relay for applying a selected polar impulse to said stepping line circuit for each time itis actuated, when such impulsing relay has been rendered efiective; a cycle controlling relay for rendering said impulsing relay effective to apply impulses to said line circuit; and circuit means for selectively actuating said impulsing relay upon the picking up of each successive stepping relay of said series in the control oifice to determine the polarity of the next impulse on said stepping circuit.

35. In a centralized trafiic controlling system of the normally at rest selector type; a normally deenergized line circuit having series of current impulses impressed thereon; a line relay in said line circuit responsive to each impulse of every series; a slow acting relay energized for each im-. pulse on said line circuit as repeated by saidline relay so as to be picked up at the beginning of each series and to remain picked up until the end of such series; a series of stepping relays; and pick up circuits for said stepping relays controlled by said line relay so as to be energized successively, one for each impulse on said line circuit, and the pick up circuit for the first stepping relay including a back contact of said slow acting relay. 7

36. In a centralized traffic controlling system of the normally at rest selector type; a line circuithaving series of positive and negative impulses impressed thereon; a three position polar relay in said line circuit actuated to one or another polar position by the positive and negative impulses respectively on said line circuit, and biased to a deenergized neutral position; a slow acting relay energized for each impulse on said line circuit irrespective of the polarity of such impulse, said relay being picked up on the first impulse of a series and suificiently slow acting to remain picked up until theend of such series; a bank of stepping relays; pick up circuits for stepping circuits of said bank; circuit means controlled by said line relay for successively energizing said pick up circuits, one for each impulse on said line circuit, in accordance with the polar positions of said line relay and dependent upon the proper response of said slow acting relay.

37. In a centralized traific controlling system of the selector type for controlling traflic on railroads; a normally deenergized stepping line circuit connecting a control ofiice and a remote station; a line relay in said line circuit at the control office; a series of stepping relays controlled by said line relay to cause said stepping relays to pick up successively, one for each impulse on said line circuit; impulsing means for l ft applying a seriesofcurrent impulses tosaid line circuit when rendered-effective; a cycle controling relay for rendering said impulsing means effective when such cycle controlling relay is picked up; a slowacting relay energized each time said 'line relay repeats an impulse on said line circuit, whereby said slow acting relay is picked up at the beginning of a series of impulses and is dropped'at the end of such series; a pick up circuit for said cycle controlling relay which can be closed only when said slow acting relay is dropped away; and a stick circuit for said cycle controlling relay including a back contact of the last stepping relay of said series of stepping relays.

38. In a centralized trafiic controlling system of the selector type for controlling traffic. on railroads, a normally open series line circuit connecting a control ofiice and a remote station; a cycle controlling relay for closing said linecircuit at the control ofiice and causing a first current impulse to be impressed thereon; a line relay in series in said line circuit at the control ofiice; a series of stepping relays controlled by said line relay to cause said stepping relays to pick up successively, one for each current impulse on said line circuit; a slow acting relay energized each time said line relay repeats a current impulse on said line circuit, whereby said slow acting relay is picked up at the beginning of a series of current impulses and is dropped at the end of such series; impulsing means rendered effective by said cycle controlling relay, only after said slow acting relay has picked up in response to said first current impulse, to remove said first current impulse and impress the remaining current impulses of a series on said line circuit; a pick up circuit for said cycle controlling relay capable of being closed only when said slow acting relay is dropped away; and a stick circuit for said cycle controlling relay including a front contact of said slow acting relay.

39. In a centralized trafiic controlling system of the selector type for controlling traffic on railroads; a series stepping line circuit connecting a control ofiice and a plurality .of field stations; means at the control ofiice for impressing a series of current impulses on'said line circuit; a line relay at each of the field stations; a slow acting relay at the first of the field stations energized each time said line relay repeats an impulse on said line circuit, whereby said slow acting relay is picked up at the beginning of a series of impulses and is dropped at the end of such series; a bank of stepping relays at each of the field stations caused to operate step-by- -step by its respective line relay when such bank means at each of the remaining "stations for initiating said bank at such station, said means including a front contact of the last stepping relay in said bank at the next preceding field station. 5 40. In a centralized trafiic controlling system of the selector type for controlling trafiic on railroads; a series stepping line circuit connecting a control office and a plurality of field stations; means at the control ofiice for impressing a series of current impulses on said line circuit; a line relay at each of the field stations; a slow acting relay energized each time said line relay repeats an impulse on said line circuit, whereby said slow acting relay is picked up at the be ginning of a series of impulses and is dropped at the end of such series; a bank of stepping relays at each of the field stations caused to operate stepby-step by its respective line relay when such bank of stepping relays is once initiated; means go at the first field station for initiating a bank of stepping relays at that station, said means including a back contact of said slow acting relay; and means for initiating the banks at each of the remaining stations, said means including a line wire connecting that station with the next preceding station and also including a front contact of the last stepping relay insaid bank at such preceding station.

1 41. In a selector system of the normally at rest type used for controlling traffic on railroads, the combination of a normally deenergized stepping circuit connecting a control ofiice and a remote station, impulsing means for applying current impulses to said stepping circuit when such impulsing means is initiated, and means for initiating said impulsing means comprising, a stick relay having a front contact which if closed starts said impulsing means into operation, an indicating contact for manifesting traflic conditions, a slow acting repeater relay for directly repeating the position of said indicating contact, a pick up circuit for said stick relay closed, whenever said indicating contact and said repeater relay are out of correspondence, and a stick circuit for said stick relay including a contact. controlled in response to impulses on said stepping circuit. 42. In a centralized traffic controlling system of the normally at rest selector type, the combination with a selector system normally at rest, of means for starting said system comprising, a stick relay having a front contact which if closed starts said system, an indicating 7 contact for manifesting trafiic conditions, a slow acting repeater relay for repeating the position of said 5. 

